hg: amber/amber: adding test to improve code coverage

[vicente.romero at oracle.com]

Changeset: 05169a7b9350
Author:    vromero
Date:      2018-06-02 19:34 -0700
URL:       http://hg.openjdk.java.net/amber/amber/rev/05169a7b9350

adding test to improve code coverage

! src/java.base/share/classes/java/lang/invoke/constant/ConstantUtils.java
! src/java.base/share/classes/java/lang/invoke/constant/DynamicCallSiteDesc.java
! test/jdk/java/lang/invoke/constant/ClassRefTest.java
+ test/jdk/java/lang/invoke/constant/ConstantUtilsTest.java
! test/jdk/java/lang/invoke/constant/IndyRefTest.java
! test/jdk/java/lang/invoke/constant/MethodHandleRefTest.java